final TableColumn column = table.getTableColumns()[i];
if (column == null) {
getLogger().warn("No table-column specification for column " +
(i + 1) + ".");
} else {
final double tu = column.traitColumnWidthTableUnits();
/* Keep track of minimum number of proportional units in any
* column which has only proportional units. */
if (tu > 0 && tu < tuMin
&& column.traitColumnWidth(this) == 0) {
tuMin = tu;